Did tyrants develop democracy in Greece?

Tyrants usually preceded democracy. They were appointed in
various cities by popular will to get rid of the aristocratic
cliques and run a city-state to the general benefit of the people
rather than the vested interested of a few. A tyrant had to
maintain a bodyguard to protect himself from the aristocrats, and
to hire them had to impose a tax on the people, which eventually
made the tyrant as unpopular as the aristocrats had been. So the
cities progressively expelled the tyrants and some tried the
experiment with democracy - with mixed success.

Failures with democracy resulted in some cases in a return to
aristocrats, monarchs or tyrants to sort out the mess. Most cities
then turned to a compromise of a form of limited democracy where
the magistrates allowed the people to vote yes or no on issues they
put before them.

No. The tyrants in Ancient Greece were autocrats in Athens who stripped away much of the democracy that had previously existed there.